Evaluation of the Severity in Patients withBronchial Asthma Using FEF25-75%

Purpose : Spirometry, because of its simplicity and reproducibility, has been used to evaluate pulmonary function in childhood asthma. We investigated whether FEF25-75% is the most sensitive parameter among other spirometric parameters in the diagnosis of pulmonary function and airway obstruction. Methods : This study included 32 children with asthma. We recorded values of spirometry(FVC, FEV1, PEFR, and FEF25-75%) before and after symptomatic improvement and compared them. The values were recorded as a percent of the predicted normal value. Results : The FEV1 value before and after symptomatic improvement was 71.7±15.6% and 83.8± 12.8%, respectively; PEFR was 75.4±18.3% and 85.0±16.0%; and FEF25-75% was 60.8±17.9% and 81.5±16.3%. According to symptomatic improvement, FEF25-75% improved more than the other spirometric parameters. Of the 40 cases of spitometric measurement before symptomatic improvement, abnormal FEV1, PEFR, FEF25-75% values were observed in 25, 17 and 28 cases, respectively. There was statistically significant difference between FEF25-75% and PEFR(P=0.005), but not between FEF25-75% and FEV1(P=0.091). After symptomatic improvement, abnormal FEV1, PEFR, and FEF25-75% values were observed in 14, 12 and 9 cases, respectively. There was statistically significant difference between FEF25-75% and FEV1(P=0.044) but not between FEF25-75% and PEFR (P=0.097). The cases of normalized values with symptomatic improvement, 11 in FEV1, 7 in PEFR and 19 in FEF25-75%. Conclusion : FEF25-75% showed the most improvement rate before and after symptomatic improvement. FEF25-75% was helpful in the assessment of treatment effectiveness and reversible bronchial responsiveness. However, this study did not suggest that FEF25-75% is the most sensitive measurement of airway obstruction.(J Korean Pediatr Soc 2001;44:916-921)